A Santa Monica Superior Court trial to determine who should oversee Beach Boy Brian Wilson's estate was averted Thursday after the celebrated singer-songwriter agreed to allow an independent conservator to be appointed over his affairs.

The agreement settles a bitter lawsuit filed May 7, 1990, by members of the entertainer's family.

The redrafting of Wilson's will in 1989--in which his former therapist, Eugene Landy, was named as chief beneficiary--caused the family to instigate the legal feud, sources said.

Wilson, chief architect of the Beach Boys' sound, was brainwashed by Landy and was mentally incompetent to name anyone to manage his affairs, the suit alleges.

The settlement calls for a "lengthy" separation between Wilson and Landy, and establishes the appointment of an independent conservator to be granted "specific and limited powers over the artist's affairs." The trial was supposed to have started Thursday.

Wilson, whose drug and mental-health problems have been widely publicized, could not be reached for comment. But his attorney, Michael Rosenfeld, said the Beach Boy was pleased with the settlement.

"Brian is happy the hostilities have finally ceased," Rosenfeld said Thursday. "He is at work already on a new record, and he's very excited about his new music."

Attorneys for both sides declined to reveal the name of the appointed conservator, whose job it will be to make certain that all provisions of the agreement are carried out.

The settlement was reached behind closed doors and sealed by the court. But sources close to the negotiations previously have speculated that Landy would not be allowed to see Wilson for at least two years.

It is also believed that all business contracts between Wilson and Landy will be terminated, including Brains and Genius, a corporate partnership created in the late 1980s to administer mutual book, record and real-estate deals.

Thursday's settlement also includes a clause allowing Wilson to revoke all previous wills, sources said.

Jody R. Leslie, attorney for Wilson's brother Carl, his mother, Audree, and his daughters Carnie and Wendy, said family members are satisfied that the agreement would allow the singer the freedom "to live his own life as he chooses."

Both parties are scheduled to return to court within two weeks to finalize provisions of the agreement.